A gas turbine engine generally includes a fan, a low pressure compressor, a high pressure compressor, a combustor section, a low pressure turbine, and a high pressure turbine disposed along a common longitudinal axis. The fan and compressor sections input work into the ambient air drawn into the engine, thereby increasing the pressure and temperature of the air. Fuel is added to the worked air and the mixture is burned within the combustor section. The combustion products and any unburned air subsequently power the turbine sections and exit the engine and may produce thrust. A low pressure spool (sometimes referred to as an “axial shaft”) connects the fan, which may also produce thrust, and a low pressure compressor and the low pressure turbine. A high pressure spool (sometimes referred to as an “axial shaft”) connects the high pressure compressor and the high pressure turbine. The low pressure spool and high pressure spool are rotatable about the longitudinal axis.
It is known to use support frames (e.g., with circumferentially distributed struts) to support the low and high pressure spools within the gas turbine engine. The support frames extend radially toward each respective spool and have a bearing disposed at a distal end, which bearing is in contact with the spool. The bearings facilitate rotation of the spools and provide a load path between the spool and the support frame.
The angular momentum (“L”) of the axial shaft, which is a function of its angular velocity (“.omega.”), imparts a torque to the frame to which the bearing is mounted. The torque, in turn, creates shear stress within the frame. To accommodate the torque and concomitant stress, the frame may include a torque box.